The conventional three-level power converting apparatus includes first and second IGBTs sequentially connected in series between an upper-side direct-current terminal P and an alternating-current terminal AC, a first coupling (clamp) diode connected between a connection point of the first and second IGBTs and an intermediate potential terminal C, third and fourth IGBTs sequentially connected in series between the alternating-current terminal AC and a lower-side direct-current terminal N, and a second coupling (clamp) diode connected between a connection point of the third and fourth IGBTs and the intermediate potential terminal C. The three-level power converting apparatus is configured to controlling the first to fourth IGBTs to be turned on and off as appropriate to output voltages in three levels from the alternating-current terminal AC (e.g., Patent Literature 1 described below).
In the conventional three-level power converting apparatus, balance resistors for potential stabilization are connected in parallel to the respective first and second coupling diodes (e.g., Patent Literature 2 described below).